In the 5-year follow-up of the pivotal SOLO-1 trial in women with advanced ovarian cancer and a BRCA1/2 mutation, maintenance treatment with olaparib led to a doubling in progression-free survival. William H. Bradley, MD, Associate Professor in the division of Gynecologic Oncology at the Medical College of Wisconsin (MCW), presented these findings at the Society of Gynecologic Oncology (SGO) 2021 Virtual Annual Meeting on Women’s Cancer.
“The initial results were extremely positive. Now the 5-year follow-up demonstrates a statistically significant, sustained progression-free survival benefit that is appreciated across both higher-risk and lower-risk groups,” said lead author Dr. Bradley, a gynecologic oncologist at Froedtert and MCW in Milwaukee.
Dr. Bradley led the landmark clinical trial locally. He sees patients at Froedtert & the Medical College of Wisconsin Clinical Cancer Center. Study participants were patients with newly diagnosed stage III or IV ovarian cancer.
Olaparib is an oral inhibitor of poly [ADP-ribose] polymerase (PARP). SOLO-1 evaluated olaparib as a 2-year maintenance therapy in 391 women with newly diagnosed ovarian cancer harboring a germline or somatic BRCA1/2 mutation who had received platinum-based therapy as their initial treatment.
In the current analysis, median progression-free survival for the overall population was sustained far beyond the end of treatment: 56.0 months with olaparib vs 13.8 months with placebo (hazard ratio [HR] = 0.33, 95% confidence interval [CI] = 0.25–0.43). Five-year progression-free survival was 48% vs 21%, respectively.
“After 5 years, almost half of patients [treated with olaparib] were progression-free, vs 20% [treated] with placebo. This is the only PARP inhibitor for which efficacy has been demonstrated beyond the completion of therapy,” indicated Dr. Bradley. “These results further support the use of maintenance olaparib as a standard of care for women with newly diagnosed advanced ovarian cancer and a BRCA mutation, and suggest the possibility of long-term remission or even cure for some patients.”